Traffic control apparatus



NOV. 17, 1936. c cH bw 2,060,798

TRAFFIC CONTROL APPARATUS I Filed Dec. 4, 1931 W/T/VE55E5. 4 INVENTOR w EiraFObcb/o ATTORNEY.

Patented Nov. 17, 1936 UNITED. STATES PATENT OFFICE,

TRAFFIC CONTROL APPARATUS Application December 4, 1931 Serial No. 578,891 13 Claims. (Cl. 177-337) My invention relates to traillc control apparatus and has'particular relation to apparatus wherein the display of signals by a right-of-way indicating system provided for a plurality of highways is responsive to the movement of traflic along the highways.

It is an object of my invention to provide for a crossing, a simple traillc control system of the type incorporating street devices that are normally actuated by traific moving awayfrom the crossing in which the actuation by such traflic of the street devices shall not result in a change in the display of signals by the signalling system.

An additional object of my invention is to provide a traific control system that is normally to be vehicle-operated but that shall operate on program when a flaw occurs in the operation of the vehicle-responsive triggers.-

According tomy invention, I provide traific control apparatus incorporating a right-of-way indicating system to display stop and go signals for a plurality of highways. Normally, go signals are displayed for certain of the highways and stop signals are displayed for certain others of the highways. A regulating device actuahle by a vehicle responsive street device is provided for controlling the period of display of the signals when the signals are changed. The regulating device is normally in such a condition that if, under the proper circumstances, the signals are changed, the go signal is displayed for a predetermined period before the other signals for the highways are displayed.

At times it may happen that the street device is defective in one of its features. In such a case it may not operate in response to vehicle actuation and consequently, the crossing at which the right-of-way indicating system is disposed will freeze with a go signal displayed for the major highway and the stop signal displayed for the minor highway.

I have, therefore, provided a contrivance for automatically checking the 'eflicacy of the street device and for correcting the defective operation thereof.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing in which the single figure is a diagrammatic view showing a circuit incorporating the principal features of my invention.

The apparatus shown in the drawing comprises a right-of way indicating system I to be disposed at the intersection of a plurality of high- 5 ways} and 5 and to display stop, caution and go signals 1, 9, I I, I3, and ii for the highways. The crossing at which the system is normally displayed is of the major-minor type and the go signals l3 are normally displayed for the major highway 3 and stop signals '9 for the minor highway 5.

The signalling system i is energized through the conducting segments ll, i9, and 2| of a program controller 23 driven from a motor 15 25 that is normally deenergized. The circuit through which the normal signals l3 and 9 are energized extends from an alternating-current supply bus 21 through conductors 29 and 3!, the movable contactor 33 of the program controller 23, the fixed segment I! of the program controller 23, conductor 35, the go signal it for the major highway 3 and the stop signal 9 for the minor highway 5, and conductor 3?, to the other alternating current power supply bus 39.

A plurality of street devices li are disposed along the minor highway 5. Each street device comprises a photo-sensitive element 43 to be normally energized from a source of radiation 15. The photo-sensitive device 53 is connected between the control electrode W and the cathode 49 of an electric discharge device 5! preferably of the grid-controlled type, and an impedance 53 of proper character is connected between the control electrode ti and the anode 55. Each electric discharge device di is supplied with en ergy from a transformer 5'8, the primary 59 of which is connected between the alternating current power supply bus lines 2? and til, and the secondary ti of which is connected between the 40 cathode 49 and the anode 55 of the electric discharge device 58 through the exciting coil $3 of a relay 85.

When a vehicie moving along the minor highway 5 intersects a beam of radiation whereby a 45 photo-sensitive device 43 is energized, the electric discharge device 5i becomes excited, and the coil 63 of the relay 65 corresponding to the electric discharge device is energized. The upper movable contactor 61 of the relay 65 then engages a plurality of corresponding fixed contacts 69 and a circuit is closed from one alternating current bus line 21 through conductors H and 73, the movable contactor 61 of the relay 65 that has been energized, conductors 15 and 11, the excitis so oriented relative to ing winding 19 of the program control motor 25, and conductor iii, to the remaining alternating current bus line it.

The motor 25 is then energized and remains energized at least as long as the beam or light remains interrupted. The movable contactor it of the program controller 23 rotates in a counterclockwise direction in engagement with the segments I'l. Is and 2| and 22 and as it rotates it engages the segment Il corresponding to the go signal I3 for a predetermined time after whichit engages in succession the segment I! corresponding to the caution signal I I' and the segment 2i corresponding to the stop signal 1 for the major highway 3 and the go signal It for the minor highway 5. when the go signal I! is displayed tor the minor highway 5 thevehicle that has heretofore interrupted the beam or radiation to actuate a street device I moves across the highway 3 and consequently, ceases to actuate the street device. However, the circuit through the motor ii is maintained closed by the engagement of a conducting segment 83 with a corresponding movable contactor ll rotated by the motor 25 through which a circuit extending from one alternating current bus line 21, through conductor 20, the movable contactor '5, the corresponding conducting segment 83, conductors 81 and 88, the coil ll of the motor 25 and conductor 8| to the remaining alternating current bus line 39.

The program control motor llthus continues in its energized tactor II through which its circuit has been closed is disengaged from its corresponding conducting segment I3. The motor 2| is normally equipped with a damping device or any well known type which need not be described herein. In the preferred practice of my invention a motor of the watt-hour meter type is utilized and with such a motor the damping device may be simply a magnet cooperating with the disc armature. It a motor of another type is utilized the damping device should be of a corresponding character. The e'iiect oi the damping device is to immediately stop the motor when the auxiliary circuit through it is opened.

The segment 83 associated with the auxiliary circuit of the motor 25, is of such character and the segments IT, IS, and II provided for the display of the signals of the right-oi-way indicatingdevice I that the movable contactor ll associated with the righto'i-way indicating controller 23 is stopped in engagement with the segment I! provided for the display of a go signal I3 tor the major highway 8, and a stop signal 8 for the minor highway I.

1 The region of normal'engagement oi the movable contactor I! with the segment I1 is preferably near the terminal of the segment at which the period of display 0! the go signal II for the major highway 3 begins, and consequently, any

Lvehicles that actuate the street device 4| associated with the minor highway 8 do not receive a go signal until period of display hi w y 3- Attentlon is called to the fact that the go signal will only be displayed for the highway i it a vehicle stops in a position to intersect the radiant beam from the lamp 4! to the photo-tube 43 for a suflicient interval 01' time to enable the movable contactor 33 to traverse the whole segment I1. ILthe vehicle merely passes through the radiant beam without stopping, the relay B5 and the motor 25 will not be energized tor a o! the go signal It for the other condition until the movable conafter at least a predetermined suiilclently long interval or time to produce a change in the signalling system. Hence, vehicles which are moving away from the intersection along lane b and do not require a change oi signals will not actuate the signalling system.

A vehicle moving away from the intersection will intersect the beam of radiations without stopping. If the vehicle moving moving away irom the intersection is one for which the signal has been changed, it will not afiect the signalling system at all, for a go signalhaving been displayed for lane 5, the motor 25 is locked in in energized condition, and it continues to rotate the brush 8!, until a stop signal is displayed for the highway, regardless of the influence 01' vehicles on the beam or radiant energy. On the other hand, if. for example, a go signal is displayed for lane I and a vehicle turns from lane 3 into lane 5, it will momentarily obstruct the radiant beam and cause relay 65 and the motor 25 to be momentarily energized. The brush 3! will then advance by a small angle relative to the sector I1, and will then stop. By the slight movement or the brush, the operation 01 the system is not substantially impaired and the cyclic change of signals will be produced only by'such vehicles as require a change of signals and stop at the intersection for a substantial interval of time. Since on the whole, through vehicles will be considerably more frequent than turning. vehicles, and since every through vehicle causes the system to be reset in itsinitial condition with the iull time period oi the lane 3 go signal available, the operation 'of the system will be substantially faultless in spite oi the slight discrepancies which may be introduced by vehicles turning at the intersection.

It is thus seen that a system is provided in which vehicles, such as those which have actuated the vehicle-actuated device and have passed through the intersection, or those which have turned from the main street into the cross street, can move away from the intersection without changing the signal display, even though the vehicle actuated device in the cross street is operated :iid begins to operate the signal changing mecha- The checking device comprises a motor II which is normally energized and by which a disc ll incorporating a conducting segment 95 is rotated. The disc 93 may, 01 course, be geared to the "motor and is preferably rotated so slowly that the conducting sector engages corresponding fixed brushes '1 once in long intervals. for example, once every hour, or once every two hours. When the conducting sector engages the brushes 91, a circuit is closed which extends from a bus line 99 o! a direct-current power supply that may be provided by suitably rectifying the alternating current supply, through conductor IIII, a brush 9'! associated with the checking disc 93, the conducting sector of the checking disc ll, a second brush 91, conductor I03, the exciting coil III! of a relay I01 and conductor I08 to the other direct-current power supply bus I I I. when the relay I01 is thus energized its lower movable contactor III is disengaged from a plurality of corresponding fixed contactors II and the circuit is opened through the sources of radiation 45 whereby the photo-sensitive elements 43 of street devices il are energized.

It is to be noted that while I have found it convenient to extinguish the sources 45 this procedure is not essential and if it is of any advantage ashutter may usually be thrown into the paths otthe beams of light that energize the photo-cells 43 by the actuation of the relay I91. In such a case another relay would of course be necessary to operate'the shutter. 7

Another movable contactor II1 of the checking relay I91 engages a plurality of corresponding fixed contacts H9 and closes a circuit that extends from one direct-current bus line 99 through conductor I2I, the exciting coil I23 of another relay I25, conductors I21, I29, and I3I, the lower movable contactors I33 oi the relays 55 associated with the street devices H, which have as yet not become energized, conductors I35 and conductor I31, contacts II 9 and the movable contactor H1 or the checking relay I91 and conductor .IIl9, to the remaining direct-current bus line III.

The relay I25 last energized is locked-in by its upper movable contactor I39 which engages corresponding fixed contacts I and which closes a circuit through the direct-current power supply and through a push button I43 that may be operated by hand 11 now, in response to the extinguishment of the sources 01' radiation '45, both relays 95 associated with the street devices 4I become energized, a circuit is closed'which extends from one direct-current bus line 99 through conductor I45, a movable contactor I41 and fixed contacts of the relay I25 that has been energized by the excitation of the checking relay I01, a resistor I49 of suitable character,-the central contactors I5I and associated fixed contacts I51 of the other relays 55 associated with the street devices 4|, conductors I53, I3I, and I29, the upper movable contactor I39 and fixed contacts I of the relay I25 that has been energized by the excitation of the checking relay I01 and the movable contactor of the push button I43 to the remaining direct-- current bus line I I I. n

The current whereby the exciting coil I23 of the relay I25 responsive to the checking relay IilI was energized, is thus short-circuited through the resistor I49 and the relay is deenergized. The system is thus reverted to its initial condition since the response to the actuation of the checking device has been proper.

It, on the other hand, one or the other of the v 7 street devices 4| should not properly respond to the extinguishment of the corresponding energizing source 45, the corresponding relay 65 would fail to be energized and the lower contactor I33 would remain in engagement with its corresponding-fixed contacts I55, the central contactor I5I of the corresponding relay 65 would remain in disengagement from its corresponding fixed contacts I51 and the relay I25 responsive to the actuation of the checking relay I01 would remain energized. 4

The relay I25 is also equipped-with a movable contactor I59 that engages a plurality of corresponding fixed contacts IGI when the relay is energized and closes a circuit extending from an alternating current bus line 21 through conductor H, the movable contactor I59 and contacts I6I of the relay I25, conductor 89, the windings 19 of the program control motor 25 and conductor 8I, to the other alternating current power supply bus 39. The motor 25 is now energized and the program control contactor 33 is rotated providing for the display of stop, caution and go signals 1, 9, II,- I3, and I5 for the highways 3 and 5 in proper succession.

If the flaw in the street device which is defective is of a temporary character only, the system is reverted to its proper major-minor operating condition the next time that the conducting segment 95 0! the checking disc 93 engages its corresponding fixed brushes 91. On the other hand, it the defect is of a permanent character, it must be properly remedied by a service man and when so remedied, the system may be reverted to its proper major-minor operation when the service man presses the push button I43 provided -i'or opening the circuit through the. coil I23 of locked-in relay I25 associated with the checking system.

My invention has been described above as applied to a particular trafilc control system. Specifically, the trafiic control system to which it has been applied is of the major-minor type.

It will be noted that essentially the outstanding features of my invention should not be limited to such a system and where my invention may be broadened by applications to other systems, I do not wish to be restricted to a trafllc control system of the major-minor type. As a matter of fact it will be observed that as regards the checking device incorporated in my improved trafllc control system, its essential elements may be widely appliedto energy translating apparatus and need not be specifically limited to traf-,

fic control apparatus. 7

As far as the traflio control feature of my Invention is concerned, it will be noted that I provide a system devoid of the ordinary time delay relays and particularly applicable to a trafllc control system incorporating photo-sensitive street devices. According to my invention a simple system is provided in which the traflic moving away from a crossing does not actuate the street devices.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. A trailic control system comprising a rightof-way indicating device to display sets of stop and go signals for a plurality of highways, means for energizing said signals, a controller incorporating a plurality of cooperative timing elements cooperating with said energizing means to regulate the display of stop and go signals for each of said highways, means for motivating said controller, said motivating means being normally deenergized whereby said controller cooperates with said signals and said energizing means to display go signals for one group of'said highways and stop signals for another group of said highways, means to be actuated by vehicles moving along said last named group of highways to coact with said energizing means to energize said motivating means, and, during a predetermined interval of time which is appreciably longer than the interval during which said yehicle-actuable means is actuated by a vehicle in motion along said highway at a normal rate of speed, to maintain said motivating-means energized only so long as said vehicle-actuable means is vehicle-actuated and after said interval of time to maintain said motivating means energized regardless of whether or not said vehicle-actuable means is vehicle actuated, whereby after said interval of time go and stop signals are successively displayed for said last named group of highways and stop and go signals are successively displayed for said first named group of highways and means cooperating with said controller and said energizing means to deenergize said motivating means after it has been energized and at the instant that the go signal reappears for said first named group of highways and the stop signal reappears for said last named group of highways.

2. A traffic control system comprising a rightof-way indicating device to display sets of stop and go signals for a plurality of highways, means for energizing said signals, means cooperating with said energizing means to regulate the periodicity of thedisplay and activity of said stop and go signals for said highways, means for motivating said regulating means, said motivating means being normally deenergized whereby said regulating means cooperates with said signals and said energizing means to display go signals for one group of said highways and stop signals for another group of said highways, means to be actuated by vehicles moving along said last-named group of highways to cooperate with said energizing means to energize said motivating means, and during a predetermined interval of time which is appreciably longer than the interval during which said vehicle-actuable means is actuated by a vehicle in motion along-said highway at a normal rate of speed, to maintain said motivating means energized only so long as the vehicle-actuable means is vehicle-actuated, and after said interval of time to maintain said motivating means energized independent of said vehicle-actuable means whereby after said interval of time go and stop signals are displayed successively for said last named group of highways and stop and go signals are displayed successively for said first named group of highways and means cooperating with said regulating means and with said energizing means to deenergize said motivating means after it has been energized and at the instant that the go signals reappear for said first named group of highways and the stop signals reappear for said last named group of highways.

3. A trafiic control system comprising a rightof-way indicating device to display sets of stop, caution and go signals for a plurality of highways, means ior energizing said signals, means cooperating with said energizing means to regulate the periodicity of the display and activity of said stop, caution and go signals for said highways, means for motivating said regulating means, said motivating means being normally deenergized whereby said regulating means cooperates with said signals and said energizing means to display go signals for one group of said highways and stop signals for another group of said highways, means to be actuated by vehicles moving along said last-named group of highways to cooperate with said energizing means to energize said motivating means, and, during a predetermined interval of time which is appreciably longer than the interval during which said vehicle-actuated means is actuated by a vehicle in motion along said highway at a normal rate of speed, to maintain said motivating means energized only so long as said vehicle-actuated means is vehicle-actuated and after said interval of time to maintain said motivating means energized independent of said vehicle-actuable means. whereby after said interval of time, go

,and stop signals are displayed successively for said last named group of highways and after said interval of time, stop and go signals are displayed successively for said first named group of highways, a signal being displayed before each change periodicity and activity of the display of said stop and go signals for said highways, means for motivating said regulating means, said motivating means being normally deenergized whereby said regulating means cooperates with said signals and said energizing means to display go signals for one group of said highways and stop signals for another group of said highways, means to coact with vehicles moving along said last-named group of highways to cooperate with said energizing means to energize said motivating means, and, during a predetermined interval of time which is appreciably longer than the interval during which said vehicle-actuable means is actuated by a vehicle in motion along said highway at a normal rate of speed, to maintain said motivating means energized only so long as said vehicle-actuable means continues to be vehicleactuated, whereby after said interval of time go and stop signals are displayed successively for said last named group of highways and stop and go signals are displayed successively for said first named group of highways, additional means cooperating with said energizing means to energize said motivating means when a vehicle, having actuated said vehicle responsive means has ceased to actuate said means and has advanced in response to the display of a go signal for said last named group of highways and means cooperating with said regulating means and with said energizing means to deenergize said motivating means after it has been energized and at the instant that the go signals reappear for said first named group of highways and the stop signals reappear for said last named groupof highways.

5. A traffic control system comprising a rightof-way indicating device to display sets of stop and go signals for a plurality of highways, means for energizing said signals, a sectored disc, contacting means cooperating with said disc and with said energizing means to regulate the periodicity and activity of the display of said stop and go signals for said highways, means for motivating said contacting means relative to said disc, said motivating means being normally deenergized whereby said disc and contacting means cooperate with said signals and said energizing means to display go signals for one group of said highways and stop signals for another group oi said highways, means to be actuated by vehicles moving along said last-named group of highways to cooperate with said energizing means to energize said motivating means, and, during a predetermined interval of time which is appreciably longer than the interval during which said vehicle-actuable means is actuated by a vehicle in motion along said highway at a normal rate of speed, to maintain said motivating means energized only so long as said vehicle-actuable means is vehicle-actuated and after said interval of time to maintain said motivating means energized independent of said vehicle-actuable means,

whereby, after said interval of time, go and stop signals are displayed successively for said lastnamed group of highways and stop'and go signals are displayed successively for said first named group of'highways, a second sectored disc and contacting means cooperating with said second disc and with said energizing means to deenergize said motivating means after it has been energized and at the instant that the go signals reappear for said first-named group of highways and the stop signals reappear for said last-named group of highways, said last-named contacting means being motivated relative to said lastnamed disc by the motivating means for said first-named contacting means relative to said first-named disc.

6. In translating apparatus of a type incorporating a trigger element, including a photo-sensitive device and means for exciting said photosensitive device, an operative system and means to respond to an actuation of said trigger element to actuate said operative system to perform its operation, means for periodically deenergizing said exciting means to actuate said trigger element to test the efficacy of said trigger and said trigger-responsive means and means to respond to the ineflicacy of said trigger or said triggerresponsive means to actuate said operative system to sufficiently perform the operations of said translating apparatus to render it useful for the purpose for which it is intended.

7. In combination with a photo-sensitive device, a source of radiations for normally exciting said photo-sensitive device, an operative system and means responsive to a decrease in'the radiation impinging on said photo-sensitive device to actuate said operative system to perform its operation, of means for periodically deenergizing' "said source of radiation to test the efficacy of said photo-sensitive device and said means responsive thereto and means to respond to the inefiicacy of said photo-sensitive device or said means responsive thereto to actuate said operative system to sufficiently perform its operations and to render it in this condition useful for the purpose for which it is intended.

8. In combination with a photo-sensitive device, means for exciting said photo-sensitive device, an operative system and means responsive to a change in the state of excitation of said photosensitive device to actuate said operative system to perform its operation, of means for changing the state of excitation of said photo-sensitive de-- vice to test the eiiicacy of said photo-sensitive device and said means responsive thereto and means to respond to the inefiicacy of said photosensitive device or said means responsive thereto to actuate said operative system to sufliciently perform its operations to render it useful for the purpose for which it is intended.

9. A traflic control system comprising right-ofway indicating means to display stop and go signals for a plurality of highways, means for energizing said indicating means, means cooperating with said energizing means and said indicating means for regulating the display of said stop and go signals for said highways, means to be vehicle actuated for controlling the activity of said regulating means, means for periodically actuating said vehicle-actuable means artificially in the same manner as it would be actuated by vehicles to test the efficacy thereof, said means to respond to the inefiicacy of said vehicle actuable means to actuate said regulating means to produce a sequential display of stop and go signals for said highways.

10. A traffic control system comprising rightof-way indicating means to display stop and go signals for a plurality of highways, means for energizing said indicating means, means cooperating with said energizing means and said indicating means for regulating the display of said stop and go signals for said highways, means associated with certain of said highways and comprising a photo-sensitive device and means for exciting said photo-sensitive device, said exciting means to be rendered inactive by vehicles moving along said highways for controlling the activity of said regulating means, means for periodically rendering said exciting means inactive artificially in the same manner as it is rendered inactive by vehicles to test the efflcacy of said controlling means and means to respond to the ineflicacy of said controlling means to actuate said regulating means to produce a sequential display of stop and go signals for said highways.

11. A trafllc control system comprising a rightof-way indicating device to display sets of stop and go signals for a plurality of highways, means for energizing said signals, means cooperating with said energizing means to regulate the periodicity of the display and activity of said stop and go signals for said highways, means for motivating said regulating means, said motivating means being normally deenergized whereby said regulating means cooperates with said signals and said energizing means to display go signals for one group of said highways and stop signals for another group of said highway, means to be actuated by vehicles moving along said last-named group of highways to.cooperate with said energizing means to energize said motivating means, and, during a predetermined interval of time which is appreciably longer than the interval during which said vehicle-actuable means is actuated by a vehicle in motion along said highway at a normal rate of speed, to maintain said motivating means energized only so long as said vehicle-actuabie means continues to be vehicle-actuated, whereby after said interval of time go and stop signals are displayed successively for said last named group of highways and stop and go signals are displayed successively for said first named group of highways and means cooperating with said regulating means .and with said energizing means to deenergize said motivating means, after it has been energized, and to leave it in such a condition that the go signal is displayed for said first-named group of highways, and, when said motivating means is energized by a subsequent actuation of said vehicle-responsive means said go signal will continue to be displayed at least for a predetermined period of time.

12. A traffic control system comprising a rightof-way indicating device to display stop and go signals for a plurality of highways, a stop signal being normally displayed for one of said highways, means for varying the display of said signals, means to be actuated by trafilc moving on said last-named highway for energizing said varying means to limit the display of said stop signal to a predetermined interval of time and to follow it by the display of a go signal for said last-named highway, said varying means being energized only while vehicles actuate said 'vehicle-actuable means during the predetermined interval of time to which the display of said stop signal is limited after actuation of said vehicle-actuable means, and means for energizing said varying means,

- independent of said vehicle responsive means as long as a go signal is displayed for said highway.

13. A tramc control system comprising a rightot-way indicating device to display sets of stop and go signals for a plurality of highways, means for energizing said signals, a sectored disc, contacting means cooperating with said disc and with said energizing means to regulate the periodicity and activity of the display of said stop and go signals for said highways, means for motivating said contacting means relative to said disc, said motivating means being normally deenergized whereby said disc and contacting means cooperate with said signals and said energizing means to display go signals for one group of said highways and stop signals for another group or said highways, means to be actuated by vehicles movin along said last-named group of highways to cooperate with said energizing means to energize said motivating means, and, during a predetermined interval of time which is appreciably longer than the interval during which said vehicle-actuable means is actuated by a vehicle in motion alon said highway at a normal rate of speed, to maintain said motivating means energized only so long as said vehicle-actuable means is vehicle-actuated and after said interval of time to maintain said motivating means energized independent of said vehicle-actuablc means, whereby, after said interval of time. go and stop signals are displayed successively for said last-named group of highways and stop and go signals are displayed successively for said first-named group 0! highways, and means cooperating with said motivatin means to d'eenergize said motivating means alter it has been energized and at the instant that the go signals reappear for said first-named group of highways and stop signals reappear for said last-named group of highways.

EZRA I. CRITCHLOW. 20 

